This invention relates to a semiconductor device, in particular, to a semiconductor device having a plurality of fin diffused regions at a channel portion and to a manufacturing method thereof.
A related semiconductor device employing a multi channel fin structure is manufactured by the following steps.
At first, a hard mask is formed on a substrate and then it is patterned into a shape corresponding to an active region by photolithography.
Next, the substrate is etched by use of the patterned hard mask to define the active region.
Subsequently, the hard mask is reduced (or minified) by means of isotropic etching.
Then, a first dielectric film is formed to fill an element isolation region and embed the hard mask.
Next, the first dielectric film is planarized and polished using chemical mechanical polishing (CMP) while a surface of the hard mask is used as a planarization end point.
Next, the first dielectric film and the hard mask are patterned to form a dummy gate pattern by photolithography.
Then, a second dielectric film is formed to embed the dummy gate pattern. The second dielectric film is planarized using the CMP while the surface of the hard mask is used as a planarization end point.
After the hard mask is selectively removed, the substrate is etched using the first and the second dielectric films as a mask to form a central trench.
Next, the first and the second dielectric films are partly removed to align a surface position of them with a bottom position of the central trench.
Subsequently, a gate film and a gate conductive layer are formed. The gate conductive layer is patterned by the photolithography to form a gate electrode.
As mentioned above, the related semiconductor device employing the multi channel fin structure is manufactured. Such a method is disclosed in Japanese Laid-Open Patent Publication No. 2006-13521.
On the other hand, it is known as another related method to form a multi channel fin structure by use of side walls. Such a method is disclosed in Japanese Laid-Open Patent Publication No. 2006-196617.